1. Field of the Invention
The present invention relates to a multi-function time measurement device having hands.
2. Description of the Related Art
Conventionally available as a multi-function time measurement device having hands is an electronic watch having an analog indicator chronograph function, for example.
Such an electronic watch has, for chronograph purposes, a chronograph hour hand, a chronograph minute hand, and a chronograph second hand, starts time measurement at the pressing of a start/stop button, causing the chronograph hour hand, the chronograph minute hand, and the chronograph second hand to turn. When the start/stop button is pressed again, the electronic watch stops time measurement, thereby stopping the chronograph hour hand, the chronograph minute hand, and the chronograph second hand and indicating a measured time. With a reset button on the electronic watch pressed, the measured time is reset, and the chronograph hour hand, the chronograph minute hand, and the chronograph second hand are reset to zero positions (hereinafter referred to as zero reset).
The electronic watch further has a function of automatically stopping the chronograph hour hand, the chronograph minute hand, and the chronograph second hand at a maximum measurement time, for example, at a watch hand start position for the time measurement. With this function, no power is consumed in vain even if the user forgets pressing the start/stop button in time measurement.
The conventional electronic watch having the analog indicator chronograph function includes, in its body, a motor for driving hands for indicating standard time and a motor for driving watch hands for indicating the chronograph. Furthermore, a button battery is included as a driving power source for the motors, etc.
When there is a plurality of watch hands for indicating the chronograph, each hand has its own motor, and the zero resetting of the chronograph depends on the zero resetting speed of each motor, and as a result, an overall zero resetting speed is substantially slowed. Since operating a number of motors consumes a great deal of power, a high capacity battery or a plurality of button batteries are contained. A bulky electronic watch thus results.
Electronic watches, equipped with a generator, as a driving power source, converting mechanical energy into electrical energy, are today available. If such a generator is contained in the electronic watch having the analog indicator chronograph function, the generator requires a large space to meet a large power consumption as described above. The electronic watch becomes bulky and such a system is not yet in practical use.
It is an object of the present invention to provide an electronic watch which is free from the above problem, is compact and is operated from small power.
A time measurement device of the present invention, includes a first motor for indicating standard time, a second motor for indicating a chronograph, a generator which generates driving power for driving the first and second motors by converting mechanical energy into electrical energy, and a zero reset mechanism for mechanically resetting the chronograph to zero.
In accordance with the present invention, the time measurement device permits the chronograph to measure any elapsed time while indicating standard time. Since the zero resetting of the chronograph is mechanically carried out, a zero resetting operation is instantaneously performed, and a single motor drives a plurality of chronograph hands. Compared with the conventional art that employs a plurality of motors for driving a plurality of hands, power consumption is greatly reduced. With this arrangement, a unit for converting mechanical energy into electrical energy works as a driving power source for the motor, and the generator is thus made compact, and the time measurement device is accordingly made compact.
In a time measurement device of the present invention, the zero reset mechanism includes a zero reset lever for resetting the chronograph to zero and an operating cam, arranged approximately in the center of the body of the device, for operating the zero reset lever.
In accordance with principles of the present invention, the entire zero reset mechanism is made compact and the body of the time measurement device is accordingly made compact, because the operating cam is arranged approximately in the center of the body of the device. With this arrangement, a great deal of flexibility is permitted in the layout and location of buttons.
A time measurement device of the present invention, includes a power source for supplying the driving power, generated by the generator, to the first and second motors. The power source includes a first power source unit and a second power source unit, charged with the driving power generated by the generator, for respectively supplying power to the first and second motors, and wherein the storage capacity of the second power source unit is smaller than the storage capacity of the first power source unit. Alternatively, the power source includes a first power source unit, charged with the driving power generated by the generator, for supplying power to the first and second motor, a voltage multiplication circuit for multiplying the driving power charged at the first power source unit, a voltage multiplication control circuit for controlling the voltage multiplication of the voltage multiplication circuit, and a second power source unit, charged with the driving power multiplied by the voltage multiplication circuit, for supplying power to the first and second motors.
In accordance with the present invention, since the power source once stores the driving power, generated by the generator, to supply each motor with the driving power, the time measurement device continuously operates for an extended period of time even when the generator is inoperative. The second power source unit, having the storage capacity smaller than that of the first power source unit, is charged, and the voltage of the second power source unit instantaneously rises and becomes high enough to drive the time measurement device, driving the first and second motors. With the voltage multiplication circuit used, the voltage, multiplied by the voltage multiplication circuit, charges the second power source unit, driving the motors, even when the charge voltage of the first power source unit is lowered, and the time measurement device continuously operates for an extended period of time.
In a time measurement device of the present invention, the chronograph includes a indicator having at least two units of time.
In accordance with the present invention, besides the display of standard time, time is presented in units of time of tenth second and 12 hours.
In a time measurement device of the present invention, the indicator is driven by the second motor.
In accordance with the present invention, the zero resetting of the chronograph is mechanically carried out. Since the indicator is driven by the second motor, a unit for converting mechanical energy into electrical energy works as a driving power source for the motor.
In a time measurement device of the present invention, the indicator includes train wheels.
In accordance with the present invention, since the indicator is operated through train wheels, a smooth operation is permitted in the time measurement device.
In a time measurement device of the present invention, the generator includes a generator rotor and a generator coil.
In accordance with the present invention, the generator rotor is rotated, generating the motor driving power in the generator coil by electromagnetic induction.
In a time measurement device of the present invention, the generator rotor is rotated by an oscillating weight.
In accordance with the present invention, the charging of the motor driving power is automated, because the generator rotor is rotated by the oscillating weight.
In a time measurement device of the present invention, the time measurement is a wristwatch.
In accordance with the present invention, the time measurement is constructed as a chronograph which is compact and free from battery replacement.